NO. 6 EAR EXOSTOSES HRDLICKA 5 



conclusion, but points to the probable influence of " hereditary ten- 

 dency ", without intimation as to what he means by this term. 



Miss Studley (1881), in a study of 22 adult Indian crania from 

 Coahuila, Mexico (15 male, 7 female), found ear exostoses in 7 of 

 the males, in none of the females. 



In 1864, 1875, 1885, 1889, 1892 and again in 1893, attention to ear 

 exostoses, particularly in American crania, is called by Rudolf Vir- 

 chow. Among 134 mostly deformed (" flat-head ") skulls from Ancon, 

 Peru, he found 18 (13.4 percent) with one or more bony tumors in 

 the external auditory canal. Virchow accentuates the fact that these 

 growths start generally from the tympanic-ring portion of the meatus. 

 In discussing their causation he is at first strongly inclined to associate 

 them with arthritis deformans. Later he evidently weakens in this 

 opinion and believes (1893) that they "are plainly products of a 

 pathological nature " ; that " like all exostoses, they owe their inception 

 to a pathological irritation restricted to the pars tympanica " ; that pos- 

 sibly they may have some connection with chronic arthritis deformans, 

 also with multiple exostoses of the skeleton ; that mechanical causes 

 such as suggested by Seligmann may have a favoring efifect on their 

 production ; that they are " examples of disturbed development, which 

 probably begins in and proceeds from the end parts of the annulus 

 tympanicus " ; and that head deformation is without efifect on their 

 production. 



Politzer (1889) reports a case of an aural exostosis in a skull from 

 Borneo. He gives considerable attention to the subject of ear exostoses 

 in his well-known Textbook and in other writings. He failed to find 

 any instance of the abnormality in over 1,000 crania of Whites. 



Hartmann (1893) reports 14 cases of bony ear tumors in a little 

 over 9,000 White patients (German), or about 1.5 percent. 



An extensive series of observations on these abnormalities is pub- 

 lished by Ostmann (1894). His report extends to 2,633 skulls, on 

 2,320 of which he made personal observations, the others being taken 

 from various other authors. The specimens were in the main those 

 of the Konigsberg, Berlin, Halle, Senkenberg, Darmstadt, and Breslau 

 anatomical collections, and the series comprised skulls of 1,054 Euro- 

 peans, 516 Egyptians, 491 Asiatics, 267 Negroes, 113 Australians 

 and Pacific Islanders, and 202 American Indians. 



In this material bony outgrowths in the auditory meatus were found 

 in but 16 crania, of which 13 (6.4 percent) were American, 2 (1.8 

 percent) Polynesian (both Hawaiians), and i (0.2 percent) Egyp- 

 tian. No exostoses were found in the Negroes, the Asiatics, or the 

 Europeans. 



